Cheat Mode:
Hold R + L + Y + Down for three seconds to toggle the following cheats on and off.

God Mode:
Press R, R, R, L, L, L, R, L, Y, R.

Auto-win:
Press R, R, L, L, R, R, Y, Y, Y.

Level Select:
Press Y, Y, Y, L, R, L, L, R, L, R, R, L, R, L, L, R, L, R, L, L, R, L, L, R, L, R, R, Y, Y to unlock the "Bling" profile with all levels unlocked.

Fog of War:
Press R, L, R, R, L, L, Y, Y, L, R.

Decrease Speed by 50%:
Press L, L, L, L, L, Y, Y, Y, Y, R.

Increase Speed by 200%:
Press R, R, R, R, R, L, Y, R, R, R.

Additional 100 Gold:
Press L, R, R, R, R, L, Y, L, L, L.

Additional 100 Souls:
Press R, L, L, L, L, R, Y, R, R, R.

1000 Gold and Souls:
Press R, R, L, R, R, Y, Y, Y, L, L.

Thanks to Revolution reader Paul Krafft!